/**
 * Created with IntelliJ IDEA.
 * Description: 第六题
 * User: 姚东名
 * Date: 2024-11-16
 * Time: 9:59
 */
import java.util.Scanner;
public class Demo1 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int total = (n / 15) * 2;
        System.out.println(total);
    }
}
